1. Field of the Invention
This invention relates generally to the field of orthopedic devices. More specifically, it relates to an orthopedic device allowing support for assisting in the stabilization and proper healing of ulcerative or pre-ulcerative conditions, post-operative off-loading of forefoot, wounds on the foot, or other conditions of the foot, especially for diabetic patients.
2. Brief Description of the Related Art
The human foot contains more than 26 bones, 33 joints, and more than a hundred muscle, tendons and ligaments. A foot is generally split up into three separate areas; hindfoot, midfoot, and forefoot. The hindfoot contains the talus (or ankle bone) and the calcaneus (or heal bone). Midfoot consists of five bones; the cuboid, navicular, and three cuneiform bones. Together the bones of the midfoot form the arches of the foot. Finally, the forefoot is composed of five toes and the corresponding five proximal long bones forming the metatarsus. Four of the toes are comprised of three phalange bones and the fifth toe (the big toe) has two phalange bones.
Wounds to the foot can be somewhat common injuries. Wounds can either be internal or external and can be caused by varying factors. For example, external wounds can be produced from external trauma, lacerations or burns. Some of these wounds can be deliberate, such as an incision for surgery. Other wounds can be unintentional, such as cuts. Finally, there are wounds caused by friction/pressure, such as foot ulcers. In fact, excessive pressure is a leading cause of ulcers in diabetic patients.
Every type of wound has the potential to cause additional complications to the affected foot. One major complication that physicians commonly have to address is infection. There are many different types of foot infections that vary in levels of complexity. To prevent injuries from getting worse, it is essential that physicians and patients have access to areas where a wound exists in order to properly care and treat the foot. It is also imperative that the area where the foot is wounded does not receive additional force that may aggravate existing issues or cause new problems.
Patients with diabetes are faced with especially difficult challenges when it comes to foot wounds. One such problem is called neuropathy or polyneuropathy, which is damage to the nerves caused by high blood sugar levels. Individuals with neuropathy or polyneuropathy suffer from a loss of feeling in the plantar surface, or bottom of the foot, which may extend from the toes up the foot to the heel and eventually up the leg. Because of this loss of protective sensation, a sense of when something is harmful to the foot, diabetic patients are especially susceptible for developing pressure ulcers.
Diabetes may also lead to many different vascular diseases, such as peripheral arterial disease (PAD). PAD occurs when narrowed arteries reduce blood flow to limbs. This reduced blood flow results in extremities, usually feet and legs, receiving insufficient blood flow to function properly. Symptoms include painful cramping after activities, such as climbing stairs, leg numbness or weakness, and sores on toes and feet that don't heal.
Diabetes patients experience varying degrees of vascular diseases and neuropathy. 60-70% of diabetics have mild to severe forms of nerve damage. In extreme cases, patients have little to no feeling in their feet. Lack of sensitivity combined with increased pressure and poor circulation often cause wounds to form and or increase in severity. For example, when a wound develops, patients may be unaware of the wound, resulting in the patient continuing to apply external factors that further aggravate the wounds. Further aggravation of the wound can potentially lead to additional tissue damage, ulcers, even infection, and often amputation. The most common complication leading to hospitalization in diabetic patients is foot ulcers.
Diabetes affects approximately 8.3% of people in the United States (about 26 million people), including approximately 7 million undiagnosed people. In 2010, 1.9 million new cases of diabetes were diagnosed in individuals twenty years of age and older. It is estimated that diabetes affects 250 million people worldwide. 1 in 4 patients with diabetes develop foot ulcers with over 50% requiring hospitalization.
Once infection sets in, amputation may be the only option for the patient's survival. Over 80% of lower limb, non-traumatic amputations occur in patients with diabetes. Approximately 1 in 5 foot ulcers will require amputation. Every year more than 82,000 amputations are performed on diabetics in the United States. Worldwide someone loses a limb to diabetes every 20 seconds. For diabetic patients the 5 year mortality rate after a limb amputation is 68%, second only to lung cancer. According to the Centers for Disease Control and Prevention, diabetes contributed to a total of 231,404 deaths in 2007.
Diabetes has national economic detriments, in addition to the physical complications. The Centers for Disease Control and Prevention estimated the total direct medical costs to be $116 billion in 2007. Indirect costs were estimated to be $58 billion in 2007. These staggering numbers necessitate the creation of ways to reduce, heal and prevent foot wounds, both in diabetic patients and in the general population.
Currently, there are several different types of shoes (for example, U.S. application number 20040031169, published 2004 and U.S. Pat. No. 5,566,479, granted 1996), boots (for example, U.S. Pat. No. 5,078,128, granted 1992, 5,329,705, granted July 1994, U.S. Pat. No. 5,378,223, granted January 1995, U.S. Pat. No. 5,464,385, granted November 1995, and 5,761,834, granted June 1998), and orthotic inserts (for example, U.S. App. No. 20040103561, published June 2004 and U.S. App. No. 20040194352) that attempt to reduce foot wound injuries, heal existing wounds and prevent future injury. While each specific embodiment has its own advantages and disadvantages, they all share common disadvantages. One such disadvantage is that there are still times when pressure and/or friction are applied to the wound site. Each embodiment also requires a patient to physically remove the device in order to gain access to the wound site. Finally, each embodiment generally lacks adaptability to change as the wound site changes. There are also significant stability issues with prior art designs.
Another widely established method, called the total contact cast (TCC), has widely been used for off-loading planter ulcers. Developed in the 1950s, the application and removal takes a number of time consuming steps. A patient must endure two applications, inner and outer, of plaster. Once the plaster is applied the patient has to wait for up to a 24-hour period before they can apply any weight to the TCC. Removal of the cast is also a time consuming process that must occur at least once a week. While the TCC is applied, the patient and the physician do not have access to the wound site. Additionally, the TCC cannot adapt to the changing circumstances of the wound without going through the tedious removal and application of the cast. Finally, the cast has the potential to cause additional ulcers or wounds in new locations because of its inability to adjust the pressure applied to the foot and leg.
Shoes, such as the DARCO® Ortho-Wedge, promote healing by shifting the weight from the forefoot to the midfoot and heel. Generally used with VELCRO®, these shoes allow for easy removal and application but still lack the ability for easy access while the shoe is on. Another disadvantage associated with these shoes is that they can't adapt as the wound adapts. In addition, the shoes can be highly unstable for patients with reduced sensitivity in their feet, such as diabetic patients. This lack of stability can cause a patient to fall, trip or otherwise put themselves at greater risk to receive additional injuries or wounds.
The prior art lacks a device that offloads the pressure from a patient's forefoot, but maintains stability while in use. Prior art also lacks adaptability as the wound changes. Finally, there is a need for a shoe that allows access to the affected area while in use.
However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the field of this invention how the shortcomings of the prior art could be overcome.